Metals And Non - Metala

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QI. Define 1. Metal:- The element which can form positive ions by the loss of electrons is called metal. Iron and copper are metals. 2. Non metals:- The element which can form negative ions by the gain of electrons is called non metal. Phosphorus and sulphur are non metals. 3. Metalloid: - The element, which shows the properties of metals as well as those of nonmetals, is called a metalloid. Silicon, germanium are metalloids. 4. Mineral: - The natural material in the earth in which a metal or its compounds occur is called mineral. 5. Ore:- The mineral from which a metal may be extracted profitably is called an ore. 6. Gangue:- The unwanted material present in an ore is called Gangue. 7. Reduction:- The process of obtaining a metal from its oxide is called reduction. 8. Refining:- The purification of a metal is called refining. In this process, the impurities present in the metal are removed. 9. Metallurgy:- The process of extraction of metals from their ores and refining them is called metallurgy. QII. Give Reasons:1. All ores are minerals, but all minerals are not ores. Explain Ans. 1. The natural material in the earth in which metal or its compounds occur is called mineral. 2. The mineral from which a metal may be extracted profitably is called an ore. Hence, all ores are minerals, but all minerals are not ores. 2. German silver is used in making heaters and resistors. Ans. German silver is used in making heaters and resistors because 1. It is an alloy of 50% copper, 25% nickel and 25% Zinc. 2. Due to this combination the alloy has high electrical resistance. 3. Metals are good conductors while non – metals are bad conductors of electricity. (T.B) OR Metals are good conductors of electricity. Ans. 1. The electrons in the outermost orbit of the atoms are free to move thought the metal. 2. In the case of a metal wire, these electrons move from one end to the other end of the wire. 3. When the potential difference is applied on one end of the metal wire the movement of the electrons constitute electric current. 4. Hence, metals are good conductors of electricity. 5. Non – metals do not possess such free electrons. Hence, non – metals are poor conductors of electricity. 4. Metals are good reducing agents. Ans. 1. When an element losses electrons, it acts as a reducing agent. 2. The atoms of metals have less than four electrons in their outermost orbit. 3. They can form positive ions by losing these electrons. Hence, metals are good reducing agents. 5. Non – metals are good oxidising agents. Ans. 1. When an element gains electrons, it acts as an oxidising agent. 2. The atoms of non – metals have more than four electrons in their outermost orbit. 3. They can form negative ions by gaining these electrons. Hence, non – metals are good oxidising agents. 17

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6. Calcium is more reactive than aluminium Ans. 1. Reactivity of a metal depends on number of electrons in their outermost orbit. 2. Less the number of electrons, more is the reactivity. 3. Calcium has two electrons in the outermost orbit, while aluminium has three electrons in the outermost orbit. Hence, calcium is more reactive than aluminium. 7. Sodium is more reactive than aluminium. Ans. 1. Reactivity of a metal depends on number of electrons in the outermost orbit. 2. Less the number of electrons, more is the reactivity. 3. Sodium has one electron in the outermost orbit, while aluminium has three electrons in the outermost orbit. Hence, Sodium is more reactive than aluminium. 8. Chlorine is more reactive than phosphorus. Ans. 1. Reactivity of non metals depends on number of electrons in the outer most orbit. 2. More the number of electrons, more is the reactivity. 3. Chlorine has seven electrons in the outermost orbit, while phosphorus has five electrons in the outermost orbit. Hence, chlorine is more reactive than phosphorus. 9. Metals are malleable and ductile. Ans. 1. Metals occur in the solid state. 2. The atoms of metals have an ability to cling together. 3. They have high tensile strength and has the ability to withstand high force and pressure. Hence, metals are malleable and ductile. 10. Duralumin and Magnalium are used to make aircrafts. Ans. 1. Duralumin and Magnalium are light and strong. 2. They resist corrosion and have load bearing strength. Hence, Duralumin and Magnalium are used to make aircrafts. 11. The graphite rods used in the electrolytic extraction of aluminium need frequent replacement. Ans. 1. In the electrolytic extraction of aluminium from alumina, graphite rods are used as the anode. At the anode oxygen is liberated during the electrolysis. 2. The oxygen reacts with the graphite rods and forms carbon monoxide and carbon dioxide. Thus, the graphite rods are continuously eroded. Hence, the graphite rods need frequent replacement. 12. Duralumin and Magnalium are used to prepare parts of aircrafts. Ans. 1. Duralumin and Magnalium are light in weight, but are strong. 2. They have high load bearing strength. Hence duralumin and Magnalium are used to prepare parts of aircraft. QIII. Answer the following in short. 1. Write the main ore of iron, aluminium and copper Ans. Iron 18

(T.B)

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1. Haematite (Fe2O3) 3. Magnetite (Fe3O4)

2. Limonite (2Fe2O3. 3H2O) 4. Iron Pyrites (FeS2)

Aluminium 1. Bauxite (Al2O3. 2H2O) 3. Feldspar (KAlSi3O8)

2. Cryolite (Na3AlF6)

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Copper 1. Cuprite (Al2O3. 2H2O) 2. Copper Pyrites (CuFeS2) 3. Copper glance or Chalcosite (Cu2S) 2. How is blister copper purified? Ans. 1. Blister copper is purified by electrolytically. 2. In this process pure copper plate is a cathode and impure copper is used as an anode. 3. Acidified copper sulphate solution is used as an electrolyte. 4. Impurities from anode plate go in to solution. 5. Pure copper deposits on cathode plat. The impurities settle down. 3. What is tempering of steel? Ans. The desired degree of hardness and electricity can be obtained by heating it to a particular temperature and then cooling it in different ways. This operation is known as tempering of steel. 4. Give the stages in the extraction of copper from copper ore. (T.B) Ans. The extraction of copper from the copper ore consists of following stages. 1. Concentration 2. Roasting 3. Melting 4. Purification 5. What is copper matte? Ans. The mixture of mainly cuprous Sulphide with a small of ferrous Sulphide obtained from the smelting of copper ore is called copper matte. 6. What are the different methods used for removing gangue from ores? OR Write the four methods of concentration of ores. Ans. The four methods used for removing gangue from ores are_ 1. Washing 2. Froth floatation 3. Magnetic separation 4. Chemical separation. QIV. Write short notes on 1. Steel: - The alloy of iron containing about 0.02 – 1.5 % carbon is called steel. Steel is malleable and has high tensile strength. It melts between 12000 – 15000 C. It can be welded. Types of steels Mild steel, Structural steel and tool steel are the different types of steel. Uses of steels Mild steel is used to prepare chains, anchors, wires, etc. Structural steel is used to for the construction of bridges, buildings, etc. Tool steel is used for making cutting tools, razor blades, springs, etc. 2. Iron alloy:- Iron alloys are as follows. 1. Stainless steel:Composition : It is an alloy of iron which contains 73% iron, 18% chromium, 1% carbon and 8% nickel. Properties: It has typical luster and it resists corrosion. 19

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Uses : It is used to make cutlery, utensils, tools, dairy equipment and cycle and automobile parts. 2. Tungsten Steel :Composition: It is an alloy of iron which contains 94%iron, 5% tungsten and 1% carbon. Properties: It is hard . Uses: It is used to prepare high speed cutting tools. 3. Manganese steel :Composition: It is an alloy of iron containing a considerable amount of manganese. Properties: It is very hard Uses: it is used to prepare rock drills. 4. Chrome steel:Composition: It is an alloy of iron containing chromium. Properties. It is hard and tough. Uses: It is used to prepare ball bearings, roller bearings, spares of automobiles and head of rock drillers. 3. Aluminium alloys: Aluminium alloys are as follows. 1. Duralumin:Composition: Duralumin contains about 95% aluminium, 4% copper, 1% magnesium and manganese. Properties: It is light and strong. It is shock resistant and fatigue resistance. Uses: It is used to prepare bodies and parts of aircraft, buses and tube trains. It is used to prepare castings and kitchen wares. 2. Magnalium: Composition: Magnalium contains 90% aluminium and 10% magnesium. Properties: It is light, strong and corrosion resistant. Uses: It is used to prepare beams of scientific balances, household appliances and parts of aircraft. 3. Aluminium bronze: Composition: Aluminium bronze contains about 88 – 96.1 % copper and 10.5 – 2.3% aluminium. It also contains minute quantities of iron and tin. Properties: It is hard, shock resistant and resistant to many chemicals and sea water. Uses: It is used as a pigment in paints and inks. 4. Alnico alloy: Composition: Alnico alloy contains mainly aluminium, nickel and cobalt. Properties: It is a magnetic alloy Uses: It is used to prepare permanent magnets. 4. Copper alloy:- Copper alloys are 1. Brass:Composition: Brass contains 60 – 90 % copper and 40 – 10 % zinc. Properties: It is hard, corrosion resistant. Uses : It is used to prepare utensils, pipes, hard wares, castings, carriage and condenser tubes. 2. Bronze:Composition: Bronze contains 81 – 90 % copper and 19 – 10 % tin. Properties: It is hard and corrosion resistant. Uses: It is used to prepare coins, utensils, bearings, ship fittings, statues and medals. 20

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3. German silver:Composition : German silver contains 50% copper, 25% zinc and 25% nickel. Properties: It has high electrical resistance. Uses: It is used to prepare electrical heaters and resistors. 4. Bell metal : Composition: Bell metal contains 78% copper and 22% tin. Uses: It is used to prepare bells and gongs. 5. Gun metal: Composition: Gun metal contains 88% copper, 10% tin and 2% zinc. Properties: It is very strong and resistant to corrosion. Uses: It is used to prepare guns and boiler fittings. 6. Aluminium Bronze: Composition: Aluminium bronze contains copper and aluminium. 5. Electrolytic refining of metal: Ans. In this method pure metal is take as Cathode, impure metal is take as anode, and the electrolytic bath is the metal ion solution. This method is used for the purification of metals like copper, tin, lead, gold, zinc, etc.

6. Froth Floatation; Ans. 1. Froth floatation is a physical method of concentration of an ore. 2. The finely powdered ore and a suitable oil are mixed with water in a large tank. 3. The mineral particles are preferentially wetted by the oil, whereas the gangue particles are wetted by water. 4. Air is blown through the mixture. The froth containing mineral particles is formed and floats on the top of water and can be removed. 5. The gangue settles down at the bottom. 6. This process is used to concentrate the Sulphide ores of copper, lead and zinc.

7. Magnetic Separation:Ans. 1. This process of concentration of an ore is used if the given ore is magnetic. 2. The crushed ore is brought near a magnet. 3. The mineral particles are attracted towards the magnet and cling to it, leaving behind the gangue particles. 4. Iron ore magnetite is enriched by this process.

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8. Write a short note on Blast furnace Ans. Blast furnace is used for the extraction of metals. Blast furnace is a tall cylindrical furnace. It is made up of steel and is lined from inside by fire bricks. It is about 30m high and has a maximum diameter of about 7m. The mouth of the furnace has a cup and cone arrangement for feeding the ore. There are pipes (tuyeres) at the height of about 2m from the bottom through which hot air can be passed. At the base of the furnace, there are two outlets; the upper outlet to remove the slag, while the lower outlet to remove the molten metal. 9. Chemical Separation. Ans. In this method the difference between chemical properties of minerals and gangue is used for Eg. Or of aluminium can be seperated from its gangue by this method. Bauxite + NaOH Sodium aluminates + Gangue (Soluble) (Insoluble) Q.V. Distinguish between: 1. Reducing agent and Oxidizing agent. Reducing Agent Oxidizing Agent 1. The substance that gives electrons is called 1. The substance that accepts electrons is a reducing agent. called an oxidizing agent. 2. Metals are reducing agents. 2. Non - metals are oxidizing agents. 2. Cast iron (pig iron) and Soft iron (Wrought iron) Cast iron (pig iron) Soft iron(Wrought iron) 1. The iron obtained directly from the blast 1. The iron obtained by removing impurities furnace is called cast iron. like carbon, sulphur, silicon and phosphorus 2. It contains 0.5 – 4.2 % carbon. is called soft iron. 3. It is brittle. 2. It contains negligible amount of carbon. 3. It is not brittle. 3. Cast iron (pig iron) and Steel. Cast Iron (Pig iron) 1. The iron obtained from the blast furnace is called cast iron 2. It contains. 0.5 – 4.2 % carbon. 3. It is brittle. 4. Soft iron (Wrought iron) and Steel Soft iron (Wrought iron) 1. The iron obtained by removing impurities like carbon, sulphur, silicon and phosphorus is called soft iron. 2. It contains negligible amount of carbon. 5. Metals and Non – Metals Metals Physical properties:1. Metals are solids under ordinary conditions. 2. Metals have high melting and boiling point. 3. Metals show ductility and malleability. Chemical properties:1. Metals reacts with mineral acids. 2. Metals are good reducing agents. 3. Metals form basic oxides.

Steel 1. Steel is an alloy of iron containing requisite amount of carbon. 2. It contains 0.02 – 1.5% carbon. 3. It is not brittle. It has high tensile strength. Steel. 1. Steel is an alloy of iron containing requisite amount of carbon. 2. It contains 0.02 – 1.5% carbon.

Non – Metals Physical properties:1. Non – metals are solids, liquids and gases. 2. Non – Metals have low melting and boiling points. 3. Non – metals do not show ductility and malleability. Chemical properties:1. Non – metals do not react with mineral acids. 2. Non – metals are good oxidising agents. 3. Non – metals form acidic oxides. 22

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QVI. Answer the following in briefly: 1. Give the stages involved in the extraction of cast iron. (T.B) Explain the working of Blast furnace. (Answer refer to point 2) Ans. The stages involved in the extraction cast iron are: 1. Concentration: The ore is crushed into small pieces and washed with water to remove the impurities like sand and clay. The washed ore is heated in shallow kilns in excess of air. The impurities like carbon dioxide, moisture, sulphur and arsenic are removed from the ore. Thus the ore is concentrated. 2. Smelting; The mixture of iron ore, lime stone and coke powder is introduced in the blast furnace through cup and cone arrangement. The blast hot air (about 8000 C. ) is passed through the tuyeres. The temperature inside the furnace is not the same through out. It is lowest at the top and highest at the bottom of the furnace. The following reactions take place at different temperatures. a. Coke from the mixture and oxygen from the tuyeres combine and the following reaction take place.

In this reactions heat is liberated and temperature rises up to 15000 C b. Lime stone is decomposed to calcium oxide and carbon dioxide is given out at about 9000 C.

Calcium oxide combines with silica from the ore forming calcium silicate (slag) c. The iron ore is reduced to iron at 6000 C

Being lighter than molten iron, slag floats on the surface. at the bottom the furnace slag is removed from the upper outlet and molted iron is withdrawn from the lower outlet and is then run into moulds. Molten iron obtained from the lower outlet of the blast furnace is impure iron called cast iron or pig iron. 2. How is aluminium extracted from bauxite with the help of neat and labeled diagram (TB) Describe the purification of bauxite by Bayer’s process. (Answer Refer to point1) Ans.

Extraction of aluminium from bauxite involves the following stages: 1. Purification of bauxite:- Bauxite contains impurities like iron oxide, silica etc. they are removed by heating the powdered ore in a furnace in the presence of sodium hydroxide at about 1500 C. Aluminium oxide present in the bauxite gets dissolved forming sodium aluminates. 23

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Extraction: Impurities like iron oxide and silica remain unaffected and un dissolved. These are removed by filtration. Carbon dioxide is then bubbled through the filtrate. Aluminium hydroxide separates out at a precipitate. It is then filtered, washed dried and ignited at about 15000 C to get pure bauxite known as alumina. This method of purification of bauxite is known as Bayer’s process. 2. Electrolysis of fused alumina:- Alumina obtained from the above process is dissolved in fused Cryolite and the electrolysed in an iron box, lined with carbon which acts itself as a cathode. The anode consists of graphite rods dipped in the fused mass. On electrolysis, aluminium is collected at the cathode and oxygen is liberated at the anode. Oxygen reacts with graphite rods carbon monoxide or carbon dioxide. Hence graphite rods are replaced after some days. This method was discovered by Charles Hall in 1886. 3. Refining of Aluminium: Aluminium obtained by this process is 99% pure. It can be further purified up to 99.99% by electrolytic refining. 3. How is copper matte extracted from copper pyrites? Ans. Copper matte is extracted from copper pyrites by the following stages. 1. Concentration: The crude ore contains_ Cuprous Sulphide (Cu2 S), Ferrous Sulphide (FeS), and impurities including Silica (SiO2 ). The crude ore is concentrated by froth floatation process. 2. Roasting: The concentrated ore containing Cu2 S and FeS mainly, is roasted in a limited supply of air (8000 C). Partial oxidation of cuprous Sulphide takes place. While ferrous Sulphide is oxidised to ferrous oxide.

3. Smelting: The roasted ore is them smelted in blast furnace, silica is added as a flux. The ferrous oxide combines with silica forming fusible ferrous silicate slag. The slag forms the upper molten layer which is removed. 4. The slag floats on the surface, which is removed. The lower molten layer contains cuprous Sulphide and ferrous Sulphide known as copper matte. 4. What is copper matte? How will you obtain blister copper from copper matte? Ans. Cuprous Sulphide along with a little ferrous Sulphide is called copper matte. The copper matte is mixed with silica and coke and reduced to copper in a converter, in which air is blown through the molten mass. The following reaction occurs.

Ferrous Sulphide if any gets oxidised to ferrous oxide. This reacts with sand and is removed as slag. When the conversion to copper is complete, the molten copper is cast into slabs. The escaping of sulphur dioxide gas as the metal cools, gives it a blistered appearance which is called blister copper containing 98.5% copper.

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